The present invention relates to a machine for writing microminiature interconnects having line widths of the order of nanometers into an oxide film and a nitride film on a silicon substrate.
When thin conductive interconnects are formed on an oxide film lying on a silicon substrate by a conventional method, the silicon surface is oxidized uniformly up to a certain thickness by thermal oxidation or other methods. Then, a resist material is uniformly applied to this surface. The resist material is exposed through a mask which has been photolithographically patterned by an electron-beam exposure machine or the like. Finally, unwanted silicon oxide (SiO.sub.2) is etched away. In this method, once the masking material is prepared, batch processing is enabled. Thus, a large number of devices can be processed. However, the minimum line width is limited to 100 to 200 nm by the effects of lateral etching. Furthermore, a large number of process steps such as oxidation, lithography, and etching, as described above, are necessary.
The atomic force microscope (AFM) was invented in 1986 by G. Binng, C. Ouate, C. Gerber, and others (see Phys. Rev. Lett., 56, 936 (1986)). The AFM, acting as an instrument for imaging surface topography, can create three-dimensional topographical images from samples including insulating samples at high resolution. The AFM is superior to other imaging instruments in these respects.